I. Field
The present disclosure relates generally to communication, and more specifically to an antenna system for a wireless device.
II. Background
A wireless device (e.g., a cellular phone or a smart phone) may include a transmitter and a receiver coupled to an antenna to support two-way communication. For data transmission, the transmitter may modulate a radio frequency (RF) carrier signal with data to obtain a modulated signal, amplify the modulated signal to obtain a transmit (TX) signal having the proper signal level, and transmit the TX signal via the antenna to a base station. For data reception, the receiver may obtain a receive (RX) signal via the antenna and may condition and process the RX signal to recover data sent by the base station.
A wireless device may include multiple transmitters and/or multiple receivers coupled to multiple antennas in order to improve performance. For example, multiple transmitters may simultaneously transmit multiple signals via multiple antennas to send multiple transmissions for different functions (e.g., voice and data), to achieve transmit diversity, to support multiple-input multiple-output (MIMO) transmission, etc. Multiple receivers may also simultaneously receive multiple signals from multiple antennas to recover transmissions sent for different functions, to achieve receive diversity, to support MIMO transmission, etc. The use of multiple antennas may improve performance for both data transmission and data reception.
It may be challenging to design and build multiple antennas on a wireless device due to various reasons. First, the wireless device may be portable and have a small size, and it may be challenging to fit multiple antennas in the wireless device due to the small form factor. Second, it may be challenging to obtain good performance for all antennas. Third, it may be challenging to obtain the desired isolation between multiple antennas within the wireless device.